Welcome to todays video where I tackle the repairs on my BMW E34 525td with the M51 engine. It all starts with an attempt to connect an old diagnostic PC, which initially fails. However, success comes with a Tiny ADS interface, allowing me access to vital error codes and live data.
The real challenge begins when we uncover a short caused by a coolant temp sensor leaking into the engine harness. The repair process involves addressing the damaged harness and navigating BMW’s INPA diagnostic software. Despite resolving the error codes, an incorrect reading inside the software leads us to further investigation.
Through electrical wiring diagnosis using a multimeter, we verify the integrity of the wiring and the sensor. This narrows down the problem to a potential ECU fault. Opening the ECU reveals no obvious signs of corrosion, which could be a potential cause for our issue.
Thanks for watching 🙂 I decided to make this video a bit ” slower ” than other ones so that I can dive into detail. Let me know if you liked it! As always if something I say or did is wrong, feel free to correct me in the comments 🙂
#BMWE34Repair #ECUDiagnosis #CarRepair #AutomotiveTroubleshooting #BMWRepair #AutoDiagnostics #ECURepair
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+1 on the tinyADS. It’s great. Did you buy your’s pre-built? Or did you build it on your own?
With your current troubles, measure the resistance at the pins on the ECU side of the harness with your 1000ohm resistor in place. You should see 1000ohms.
If that works, do a voltage drop test on the harness. Disassemble the ECU connector so you can access the rear of the pins at the ECU when it’s plugged in. Plug the other end of the harness in at the temp sensor. Turn the key to on. Place your multi-meter leads on the ecu and temp connector ends of ONE of the two wires. You should see 0V. If you see a larger values. There is a voltage drop occurring somewhere in the harness. Repeat for the other wire.
Really interesting stuff. Hope the ECU is OK, fingers crossed it will be.
Have you tried giving the pump fuel from your own source? It was always the first thing I done, a makeshift tank with feed and return. The vp is great at pumping but not so much at sucking and the case pressure is what drives the timing cylinder. I saw a few times (cant remember if e34) the pump which sends fuel from one side of the tank to the other failing causing low fuel problems below half full. I'm just throwing ideas out.
got the same tinyADS interface, its so good. but you can just use the cheap 20pin adapter cut it open and solder the wires to it. its a much cleaner option then the bare wires everytime.
My inpa also shows weird coolant temp values when the engine is turned off, if i turn it on everything is back to normal. I think its the way its supposed to be.
nevertheless i enjoy your videos very much!